1. Field of the Invention
The present invention relates to a method and apparatus for registering palm pattern impression impressed by each of different individuals who are subject to personal identification by use of a computer system, for the purpose of personal identification. In particular, the present invention relates to a method and apparatus for registering palm pattern impressions through simplified means that does not rely on human hands, thereby reducing the time required for the registration process.
2. Description of the Related Art
Fingerprints are said to be the physical feature information most commonly used in personal identification and personal authentication for the purpose of verifying that an individual is really the person whom he or she claims to be. Features that can be obtained from fingerprint ridges (bifurcations and endpoints) vary from person to person and do not change for life.
Because of these characteristics, a number of apparatuses have been disclosed that utilize features obtained from fingerprint ridges to conduct personal authentication. Also known are other apparatuses based on a similar concept that utilize features obtained from ridges of palm patterns existing in palms for personal authentication.
To date, several methods and apparatuses that split and register palm pattern impressions have been proposed with the aim of reducing the time required for matching palm pattern data by limiting the search area to deal with when collating palm pattern impressions.
One of these arts is disclosed in Japanese Patent No. 002944602, entitled “Method and Apparatus for Registering Palm Pattern Impression.” As shown in FIG. 8, this art splits a palm pattern impression into three regions for more efficient registration, using a pad split line that connects the impression end point 86 between the middle finger and the ring finger with the point of intersection (arm trident) 87 between the Life line 85 and the wrist-side impression end, and a base split line that is orthogonal to the pad split line and that runs through the point of intersection 88 between the Heart line 84 and the impression end. These regions are called interdigital region 81, which is the area around the roots of the four fingers; thenar region 82, which is the area around the root of the thumb; and hypothenar region 83, which is the remaining area.
The above-described conventional methods and apparatuses for registering palm pattern impressions, however, hold several problems, as described below.
The first problem is that the points to serve as reference points, e.g., the middle point between the middle finger and the ring finger, the arm trident, the point of intersection between the Life line and the impression end, and the point of intersection between the Heart line and the impression end, do not appear clearly in some palm pattern impression images with lower image quality. On these images, only experts who are familiar with the characteristics of palm patterns can infer the coordinates of these points correctly.
The second problem is that the process of splitting a palm pattern impression into regions relies on visual inspection. In other words, these arts require the intervention of human hands during the region splitting process for the registration of the images of impressed palm patterns, requiring an enormous number of man-hours by experts to build a large-scale palm pattern database.
The third problem is that the need to utilize the data registered in this palm pattern database may very often arise when palm pattern data are re-registered using a new region splitting method. Since the palm pattern database has already been built using the above-mentioned art, difficulties should be encountered in meeting such need. In order for this need to be met easily, it is necessary to limit the search areas to those that are equivalent to the three regions used in the conventional arts, i.e., interdigital region, thenar region, and hypothenar region, thereby eliminating the necessity to newly execute the region splitting process.